The present application relates to an optical film having tridimensional configuration on the top surface thereof, and a lighting device and a display unit including the same.
Because of benefits of low power consumption, space-saving, low-pricing and so on, an LCD (Liquid Crystal Display) is recently replacing a CRT (Cathode Ray Tube), which has been the mainstream of display system heretofore.
LCD is classified into a few types according to its illuminating method for displaying images. Representative example includes a transmissive LCD, in which a backlight system for image display is employed.
It is preferable for such display units to expand the color gamut thereof. For that purpose, employment of three primary color LED (light emitting diode) of blue, green and red as a light source has been proposed instead of CCFL (cold cathode fluorescent lamp). Moreover, not only the three primary color LED but four primary color or six primary color LED is proposed to be employed for wider color gamut.
To use CCFL and LED as a light source, uniformity of the in-plane distribution of luminance and color is necessary. In the case where lighting device is relatively small, a light guide plate of sidelight backlight system may be used. However, in the case where lighting device is relatively large and large light quantity is necessary, direct-type LCD backlight system, in which light sources are disposed in a direct backside portion of panels and the like, is more dominant. It is proposed to arrange a diffusion plate containing filler in a position above the light source as one of the techniques for reducing the luminance irregularity, and color unevenness in the direct type (refer to Unexamined Japanese Patent Application Publication No. 54-155244). It is proposed, as another technique, to provide a plate of which sectional configuration is uniform in one direction. (Unexamined Japanese Patent Application Publication No. 2005-326819).